This invention is directed to the fumarate salt of 4-(diethyl-3-(1-methyloctyl)-7,8,9,10-tetrahydro-6,6,9-trimethyl-6H-dibenz o[b,d]pyran-1-ol, 4-diethyl-amino)butyric acid ester, referred to in this disclosure as HGP-2 fumarate.
The hydrochloride salt of 4-(diethyl-3-(1-methyloctyl)-7,8,9,10-tetrahydro-6,6,9-trimethyl-6H-dibenz o[b,d]pyran-1-ol, 4-diethylamino)butyric acid ester (HGP-2 hydrochloride), and its use as a potential antiglaucoma agent, have been reported. See naboctate hydrochloride or simply naboctate in Pharmacological Reviews, 38(2):75-149 (1986).
However, salts of 4-(diethyl-3-(1 -methyloctyl)-7,8,9,10-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran-1-o l, 4-diethylamino)butyric acid ester have been found to be unstable and therefore generally unsuitable for pharmaceutical uses. In particular, HGP-2 hydrochloride is a highly hygroscopic amorphous semi-solid, quite unstable and requires special treatment such as storage in a desiccator to prevent rapid decomposition. Accordingly, the compound is generally unsuitable for use as a pharmaceutical agent.
Glaucoma represents a significant health problem with estimates that between 2 to 9 percent of the adult population worldwide suffers from increased intraocular pressure. Current therapy include use of so-called "beta-blockers". These drugs however are not effective for all patients and often result in undesirable side effects that include lowered pulse rate, asthma and gastrointestinal problems.
It thus would be desirable to have a new means for treatment of glaucoma.